"I surrendered," Mike Tyson says simply as the ghosts of his past swarm around us on a hazy winter afternoon in Henderson. We're only a half-hour drive from the jittery Las Vegas Strip but here, on a couch in his office, Tyson sits quietly. He rests his familiar tattooed face in the palm of his hand. After Muhammad Ali he remains the world's most recognisable boxer, and one of sport's most infamous characters. Yet Tyson looks most like a 47-year-old man trying hard to understand his tumultuous life.

He was once a frightened little boy, beaten often by his mother in a condemned building in Brownsville, Brooklyn, who turned himself into the self-proclaimed baddest man on the planet. Tyson made and then lost almost a billion dollars as the last great undisputed heavyweight champion of the world whose controlled fury in the ring was eventually disfigured by madness and violence. He has had distressing problems with women, been to jail and then imprisoned even more tightly by alcohol and drug addiction.

Now, however, Tyson taps me gently on the arm. "I surrendered to a higher power. I said: 'Help me. I can't do nothing no more. Guide me. God, whoever. I don't know what to do … '"

Tyson has long been a masterful story-teller, with his obvious intelligence and street-hustling mentality producing a spellbinding raconteur, but this is different. He is not spinning a yarn here. Tyson, instead, is remembering his four-year-old daughter, Exodus, who died during a tragic accident in 2009. His eyes fill with tears. "I'll never get over it," Tyson says. "I just can't … "

Somehow he manages to control his crying, and he wipes his eyes. "If I wasn't married I'd be very different. I'd still be that violent schmuck because that's all I once knew – how to hurt people. I used to do all that stuff and I never cared about the repercussions. But I've surrendered now. I was thinking of my daughter when …[he points to his teary gaze] … but I'm just happy I'm not that same person."

Tyson has a way of opening up now that allows the darkness to pour out of him without spreading the carnage that once trailed him wherever he went. He seems amazed he's still here, in one middle-aged piece. "What's today's date?" he asks, before recalling last Wednesday's milestone. "On the 15th, it was five months since I went straight. I've been clean five months. I just don't want to do it no more … "

Tyson admits in his relentlessly gripping autobiography, Undisputed Truth, that he is a cocaine addict whose recovery was hit by a relapse last summer. "I was sober three years," he says now, "but I wasn't living a sober life. I know guys who don't take drugs for 20 years but they still don't live a sober life. They're bad, they're manipulative, they're not conscious of other people's feelings. A sober lifestyle needs a sober consciousness. But, still, the concept of happiness is fleeting. I read this book, The History of Happiness, and they go from Homer to Kennedy to Martin Luther King and everybody has a different definition of happiness. Some people believe happiness is overcoming adversity or getting out of a bad situation. Abstaining from sex and then having sex is happiness to someone else. It's so weird."

'I look at [happiness] as just living healthily with a good moral sense.' Photograph: Jacob Kepler for the Guardian Jacob Kepler/Guardian

Has Tyson worked out his own definition of happiness? "I look at it as just living healthily with a good moral sense. Having morality. You know any self-inventory I do tells me the same thing. I look back at the life I once had and see that I didn't have an emotional problem. I had a morality problem. I was without any morals."

Reading his book which, for all its sly humour and savage eloquence, is often harrowing, it's hard to shake the images of Tyson's mother, Lorna, and his mentor, Cus D'Amato, that rise from the page. Tyson relives one of his bleakest memories at the age of seven. "I was a pudgy kid, very shy, and I spoke with a lisp. The kids called me 'Little Fairy Boy'. Once, my mother was fighting with this guy, Eddie, and it's barbaric. Eddie knocked out her gold tooth and me and Denise [his sister] are screaming. But my mother's real slick. She puts on a pot of boiling water."

Tyson looks up – and I can see the looming terror of his tale. "The next thing I know she's pouring boiling water over Eddie. He was screaming, his back and face covered in blisters. We put him on the floor. My sister takes a lighter and sterilises a needle and then, one by one, she bursts the blisters."

Forty years later Tyson remembers that he and Denise were crying. He gave his mother's burnt lover a quarter to comfort him. Eddie rose to his feet and trudged to the corner store to buy alcohol for Tyson's mother. "So you see," Tyson notes, "he rewarded her for it. That's why I was so sexually dysfunctional."

Tyson describes his mother as a formidable presence who skewed his perceptions of women. "That's why I've had to embark on a new life because I used to look upon women as being equal in a physical confrontation. I would take women very seriously. As I tried to explain in the book I didn't grow up around frightened women. If you sleep they might kill you – especially if you disrespected them. I remember my mother – boom! boom! – attacking these men. It was a violent household.

"Even today, I don't like looking at a corner of a room. I still think of being in the corner getting beaten by my mother. Back then it was like 'Holy Moly!' [Tyson laughs] but as you get older it seems funnier. But even though people think of me as 'Mike Tyson', this scary guy, I still have that fear today. That's what happens when you're a traumatised kid."

It still hurts him, but Tyson mentions his brother Rodney, who is five years older than him. Unlike Iron Mike, Rodney went into medicine and he's a surgical assistant at a hospital in California. Tyson seems stunned by his brother's achievements. "I was used to living in a slum, in a condemned building. But my brother never talks about that. It must affect him. He said to me last time we spoke: 'I heard you have a magnificent book … ' But he hasn't read it. He's just so far away from that world."

Why wouldn't Rodney read his book? "I don't know," Tyson sighs. "He's the No1 trauma guy in the country. He's awesome. He's taken bullets out of some of my friends. He's stitched them up and they've said: 'Mike do you know your brother is a surgeon … ' I say: 'Yeah, I know.'"

How often does he see Rodney? "Not much. It's the really sad part about my family. We don't have a close connection. Too many demons, too much pain."

Tyson sounds neither self-pitying nor maudlin when he says: "My mother never believed in me. Even when I started doing well in boxing and people were writing about me she thought I was insane. I'd tell her: 'Read this article, Mom.' She'd say: 'Yeah, I'll read it later … ' She didn't have any hope in me because I let her down so much. She must have wondered: 'What do these white people see in my son?'"

D'Amato, his supposed saviour, was a dark and complex figure. The sentimental version paints him as a saintly figure, a wise old trainer who rescued Tyson from juvenile prison and used boxing to instil discipline and purpose into his wayward life. But, as Tyson suggests, "there wasn't a happy muscle in his face".

Tyson nods at the memory. "He was bitter towards Angelo Dundee [who trained Ali and Sugar Ray Leonard] and all those guys. Cus wanted to be the guy everyone spoke about. You know it's crazy. If he were alive I'd never say these things. I would've made him out to be a saint because otherwise he would have killed me! I would've been so afraid and intimidated by Cus."

A giant painting of D'Amato stares down at us from the wall of Tyson's office. The previous day, Tyson had listened to an old recording of his trainer praising him but worrying, just before his death in 1985, that "he likes girls too much". Tyson cackles: "He was fucking Nostradamus … "

Tyson stresses that D'Amato made him more aware than anyone that he should be proud to be black – but he is troubled by other memories. "Cus told me that the word 'no' would be like a foreign language to me when I become world champion. I don't know if that was good advice at such a young age. Another time, when I felt no girl would ever like me, he came in with a baseball bat. He told me I'd need it to beat the women off me."

How old was he when D'Amato offered that warped perspective? "Fourteen, maybe 15. The only morality I knew was to win, to conquer, to be the best. Everything flowed from there. It made me think I should have this, or that girl should sleep with me. I was programmed that way. Can you believe this old man taught me these things? He must have been way out there.

"I watch some crazy clips of myself from back then and I can say that I probably wasn't sane for a period in my life. But Nietzsche was crazy too. He was born in 1844 and died in 1900 … but he only had sex once in his life and he got a venereal disease. He said some profound shit, man, but he was totally off his head.

"I have this book of the world's greatest letters and his mentor was Richard Wagner. But he wrote Wagner a scathing letter. He had thought Wagner was perfect but he was just a leech. Wagner was an extreme megalomaniac. Nietzsche saw through all this and said: 'Hey, you're full of shit. You're a charlatan.' Yet the day Wagner died Nietzsche saw a picture of him and said: 'I love him much … ' Nietzsche believed that the poor were supermen, the poor were the ones who could endure and strike back. Dostoevsky too. He was a like a diva but you have to remember that, in 1846, his first novel was called Poor Folk."

Tyson learned about Nietzsche and Dostoevsky, Tolstoy and Napoleon, from D'Amato and Norman Mailer. "You can be an idiot and still learn something from those guys. You didn't need to go to school to get an education around Cus and Mailer. They talked about everything from such a high position. They never come down to laymen's terms. I learnt a lot and it's helped me through all the ups and downs."

Tyson and his wife, Kiki, were once nearly broke. They went to their local supermarket in Henderson and, after all his squandered hundreds of millions, he was worried that they didn't have enough money to pay for their small cart of groceries. "I kept telling Kiki: 'Put that back' – because once, with my mother in Brooklyn, we didn't have enough. Fuck it. This lady at the till was taking items away and saying: 'Put it back!' I never forgot that feeling. My wife kept saying: 'I've got enough, trust me.' I said: 'Baby, please, I don't want to be embarrassed.' But Kiki was right. We had just enough."

From Kiki, via an elderly white drug counsellor called Marilyn and his close friend Hope, to his youngest daughter, Milan, Tyson appears to be have been rescued by females. Of course, being Tyson, his gratitude is freighted with uncertainty. "I love my boys, but my daughters make me want to be a nice person. I want my daughters to be treated the way I treat them. But I fear not being able to take care of my wife and kids the way they deserve. I fear that my life is just going to sink away and I'll just be a homeless bum. I have so many fears. I'm afraid of being desperate. But I'm trying.

"My wife gave me a perception of gratitude that I never had before. I was just a prima donna my whole life, thinking I deserved everything I got. But since then I've learned gratitude. Sometimes I still get angry because she'll be telling me: 'Remember when we didn't have this … ' Now I've got an office and stuff. This is like being in heaven compared to how we were before. But I still want more. Ain't that crazy?"

Tyson seems less crazy now than he has done for years. He's trying hard to stay straight and through his family, his one-man stage show, some acting, his book and his new company Iron Mike Promotions [IMP], Tyson has enough to sustain him. Yet he is painfully honest about the perennial danger that he will fall again. "I've had a little success with acting but I can't even enjoy it. I go somewhere with my wife and I'm scared I might get carried away and she might leave me. It's really hard to be happy … but I've got something that makes me think: 'Man, I don't want to fuck this up!'"

Tyson has lived a life which, as he says, has been "full of extreme highs and lows", and one in which, for all his faults, he has often been treated like a piece of money-making meat. What does he think of people today, having seen the best and the worst of so many – including himself? "Human beings are just a bad lot. Not everyone but the majority of people. Let's put it like this rather than in a collective sense. The people I invested the most time in disappointed me … "

Yet he stresses that his wife and Steve Lott, one of his oldest friends and now his assistant, are two of the exceptions who bolster him most. They are almost always with him as Tyson tries to turn IMP into a boxing powerhouse. Even if he continues to struggle for a promotional licence in some states, and he was barred from entering Britain last month because of his criminal record, Tyson appears determined to make his new life work.

"We're discussing this deal with Fox TV where we get 32 fights a year. Man, if that happens we'll be in the driving seat. It looks real good. This is the moment. The two shows we did recently superseded all the ratings ESPN had for their Friday night fights. But I never anticipated this thing being that difficult. Still, imagine if I was not Mike Tyson and how hard it would be then."

As the sun sinks across Nevada, Tyson shows me footage of his favourite old fighters. The office is empty but for me, Tyson and Lott and they dig out film of Panama Al Brown – the freakishly tall bantamweight of the 1920s and 1930s who supposedly had a tempestuous affair with Jean Cocteau.

Mike Tyson in make-up before recording an advertisement for WWE. Photograph: Jacob Kepler for the Guardian Jacob Kepler/Guardian

Tyson has an encyclopedic knowledge of boxing, which is at its most irresistible when he zips from one great old fighter to another, from Ted "Kid" Lewis to "Baby" Arizmendi, from Harry Greb to Jack Britton, the New York welterweight who had a reputed 350 fights. Panama Al flickers across a screen while Tyson marvels at his skill and venom. He seems happy – lost in boxing again.

The next day Tyson has to make a television advert at his office for WWE (World Wrestling Entertainment) and the contrast between 21st-century wrestling and boxing at its greatest, all those decades ago, is stark. As if to showcase the similar difference in his own life, he points out that we first need to babysit his four-year-old daughter, Milan, and her friend. "They're doing finger-painting," Tyson says while we watch the two small girls hard at work in the reception area. "And we're in charge … "

Tyson is at his warmest and most generous today and it's impossible not to like him as we fritter away the hours before the wrestling advert begins. We talk about his facial tattoo. "I just hated myself then," he says. "I literally wanted to deface myself. I went to this tattoo artist and said I wanted my face to be covered in stars. He refused. He said I have a good face."

The tattoo artist suggested, instead, that he ink a Maori tribal design on to the left side of Tyson's face. "It looks awesome. That tattoo is me. Sometimes I see people with tattoos on their face and I'm like: 'Woah, this guy is crazy!' I forget that I've got one on my face."

Tyson laughs. "In the beginning, some people were scared by it. But the bikers would shout out: 'Oh, that's beautiful man, great ink!'"

Eventually, to the delight of Milan and her friend, the make-up artist arrives. It seems poignant now, setting aside his past brutality, that Tyson should have his face covered in make-up while his daughter croons: "Don't worry, Daddy, she's gonna make you look pretty!"

Tyson looks bashful while the make-up artist powders his tattoo. "Lipstick! Lipstick!" the little girls chant, full of glee at the thought that Iron Mike will need lipstick for television. We retreat to a conference room where the WWE commercial is being shot. Tyson winks at me before he addresses the autocue, which is filled by a stream of words he needs to say out loud while being filmed.

His only mistake on the first take is to pay homage to "Cold Stone" Steve Austin – rather than the old wrestler's "Stone Cold" nickname. He does it again and again and again. By the fifth take, Tyson the pro nails it – only for the producer to inadvertently cough during the last line. Tyson needs to do it again and so he tells the unblinking camera that one of the highlights of his career was the moment he was elected to the WWE Hall of Fame. He reels off the blurb a sixth time, perfectly, only to hear that someone had knocked on the window as they walked past.

Take Seven, however, is unbeatable. The first part is done but he still needs to do another and a Q&A for the WWE.

"I need a break," he says. Tyson leads me back into his office.

It seems like he does not know whether to laugh or cry. Instead, in the quiet of a Friday afternoon, Tyson looks at me and smiles. "Imagine if that happened 20 years ago," he says of his repeated WWE takes. "I would've smashed up their cameras."

The 47-year-old former champion ponders the damage he would have done and, then, Tyson lets slip a soft laugh. "Maybe I'm making progress. Maybe, after everything, I'm doing OK."